Turn carton dimensions into a real loading plan. Twelve equipment types, multiple SKUs, pallet mode, mixed-orientation packing, a 3D load view, payload and VGM checks, chargeable weight, cost per CBM and an LCL versus FCL break-even.
Container stuffing, done properly
The reference material behind the calculator: how the packing arithmetic actually works, what every container really measures, how pallets change the problem, where weight limits bite before volume does, and how to turn a load plan into a cost decision.
Why a load plan is worth doing
Container freight is sold by the box, not by the cubic metre. That single fact is why load planning pays: every percentage point of unused space inside a container you have already paid for is money thrown away, and the difference between a plan that fills a box and one that does not is very often a whole second container on the invoice.
The arithmetic is not hard, but it is unforgiving. Cartons come in fixed sizes, containers come in fixed sizes, and the only variable you control is orientation. Turn a carton the other way round and the number that fits along the length changes, which changes the number per layer, which multiplies through the number of layers. A five-centimetre difference in a carton dimension can be worth several hundred pieces per container. Nobody does this reliably in their head.
What this calculator gives you
A real schedule
Cartons per row, per column, per layer and layer count — the numbers a stuffing crew needs, not just a total.
Orientation search
All six carton orientations tested, plus a partition that fills the leftover slabs with a different orientation.
Pallet mode
Cartons per pallet, then pallets per container, with double-stacking checked against real load heights.
Both utilisations
Volume and weight side by side, so you can see immediately which one is the binding constraint.
Compliance checks
Payload, VGM and road gross-weight warnings before the box reaches a weighbridge.
Cost per carton
Every equipment type ranked for your cargo, plus the LCL versus FCL break-even at your own rates.
The two mistakes this prevents
Booking the wrong number of containers. The most expensive error in the process, and the easiest to make by eye. A plan that shows 1,412 cartons per box against an order of 1,400 is the difference between one container and two.
Discovering the weight limit at the port. Dense cargo hits the payload ceiling long before it fills the box. A container that is 60% empty and 5% overweight gets rejected, and by then the trucking, the terminal slot and the sailing are all already committed.
Use it before you quote, not after you book. A load plan built during quoting tells you the true cost per unit and gives you a defensible freight line in your pricing. Built after booking, it only tells you what you got wrong.
Step one: the naive calculation, and why it is not enough
The obvious approach divides each container dimension by the matching carton dimension and rounds down: cartons along the length = floor(container length ÷ carton length), and the same across the width and up the height. Multiply the three and you have a total. It is correct as far as it goes, and it is what most online calculators stop at.
The problem is that it fixes the carton in one orientation and throws away everything left over. If the container is 590 cm long and the carton is 50 cm, eleven fit and 40 cm goes to waste — down the entire width and the entire height of the container. On a 40ft box that leftover strip can be several cubic metres.
Step two: search every orientation
A rectangular carton has six distinct orientations: any of its three dimensions can run along the container length, and for each of those the other two can be swapped. The calculator evaluates all six and keeps the best. When you set a this-way-up constraint the search drops to the two orientations that keep the carton upright, because tipping a carton labelled fragile or liquid-filled is not a saving, it is a claim.
Step three: partition the leftovers
This is where the tool goes beyond the standard calculation. Once the main block is placed — nL × nW × nH cartons in the best orientation — the container still contains three empty slabs that do not overlap each other:
The end slab: everything beyond the last row, running the full width and height of the container.
The side slab: everything beside the last column, running the length of the main block and the full height.
The top slab: everything above the top layer, over the footprint of the main block.
Each slab is itself a rectangular space, so each can be filled with whichever of the six orientations suits its particular shape — usually a different one from the main block, because the slab has a very different aspect ratio. The three slab counts are added to the main block. The partition guarantees no double counting, which a looser heuristic would not.
What this is not. It is a good heuristic, not a proven optimum. Three-dimensional bin packing is NP-hard: for any interesting number of cartons there is no practical algorithm that guarantees the true maximum. Commercial load-planning software uses similar heuristics with more layers of refinement. Treat the output as a strong, achievable plan rather than a mathematical ceiling — and if a warehouse team tells you they fit more, believe them and write down how.
Step four: apply the real-world constraints
Geometry produces an upper bound. Three things pull the achievable number down:
The stacking limit. A carton rated to be stacked three high must not be built six high just because the container is tall enough. The calculator caps the column height at your stated limit and reports the resulting loss.
The payload. Once cargo weight reaches the container payload, no further cartons go in regardless of space. The tool caps the load at the weight limit and tells you when weight, not volume, is what stopped it.
Working clearance. Real crews need room to move, and bracing needs space. The clearance and door-end inputs shrink the usable envelope before any packing happens, which is the honest way to model it.
Reading the utilisation figures
Volume utilisation is loaded cargo volume ÷ container internal volume. Even a perfect plan rarely exceeds 90%, because cartons are not infinitely divisible and the last partial layer is always partly air. Weight utilisation is cargo weight ÷ payload. Compare the two: whichever is higher is your binding constraint, and it tells you what to change. High volume and low weight means look for a bigger box or denser packing. High weight and low volume means the box size is irrelevant and you should be splitting the order differently.
Equipment reference
Internal dimensions vary between builders, ages and carriers, sometimes by several centimetres. The figures below are widely used planning values and are what the calculator uses by default. When a load is marginal — when one extra centimetre would add a row — get the exact figures for the container number you have been allocated.
Equipment
Internal L × W × H
Door W × H
Capacity
Tare
Max payload
20ft Standard (20GP)
5.90 × 2.35 × 2.39 m
2.34 × 2.28 m
33.2 m³
2,230 kg
28,200 kg
40ft Standard (40GP)
12.03 × 2.35 × 2.39 m
2.34 × 2.28 m
67.7 m³
3,750 kg
26,700 kg
40ft High Cube (40HC)
12.03 × 2.35 × 2.69 m
2.34 × 2.58 m
76.3 m³
3,900 kg
26,580 kg
45ft High Cube (45HC)
13.56 × 2.35 × 2.69 m
2.34 × 2.58 m
86.0 m³
4,800 kg
27,700 kg
20ft Reefer
5.44 × 2.29 × 2.27 m
2.29 × 2.26 m
28.3 m³
3,000 kg
27,400 kg
40ft Reefer HC
11.58 × 2.29 × 2.55 m
2.29 × 2.50 m
67.6 m³
4,600 kg
25,900 kg
20ft Open Top
5.89 × 2.35 × 2.34 m
2.34 × 2.26 m
32.4 m³
2,350 kg
28,080 kg
40ft Open Top
12.03 × 2.35 × 2.34 m
2.34 × 2.26 m
66.1 m³
3,900 kg
26,580 kg
20ft Flat Rack
5.62 × 2.23 × 2.21 m
open
—
2,800 kg
31,000 kg
40ft Flat Rack
12.13 × 2.40 × 2.14 m
open
—
5,000 kg
40,000 kg
EU Mega Trailer
13.60 × 2.48 × 3.00 m
2.48 × 2.95 m
101.2 m³
—
24,000 kg
US 53ft Trailer
16.15 × 2.59 × 2.90 m
2.59 × 2.79 m
121.3 m³
—
20,000 kg
The details that catch people out
Door aperture is smaller than the interior. A machine that fits inside a container may not fit through its doors. Always check the door width and height for anything rigid and oversized — that is what open-tops and flat racks exist for.
A 40ft carries less weight than a 20ft. Counter-intuitive but true: the 40ft box weighs more empty and the road limits are the same, so its payload is often lower. Dense cargo belongs in 20ft containers.
Reefers are much smaller inside. Insulation and the machinery unit eat close to half a metre of length and a useful amount of height and width. Never plan a reefer load using dry-container dimensions.
High Cube height is not free. The extra 30 cm is only useful if your carton height divides into it. A 45 cm carton gains nothing going from 2.39 m to 2.69 m — five layers either way.
45ft boxes are not universally accepted. Some trades, terminals and road networks restrict them. Confirm before you plan around one.
Floor strength is finite. Concentrated point loads from machinery need spreader boards even when the total weight is within payload.
Why palletise at all
Palletising costs you space. A pallet deck is 12 to 15 cm of dead height, the footprint rarely tiles perfectly into a container, and you carry the pallet weight as cargo. In exchange you get mechanical handling at both ends, far less damage, faster loading and unloading, and a unit load that warehouse systems can track. For most consumer goods moving through modern distribution the trade is obviously worth it. For dense, low-value, high-volume goods being hand-stuffed at both ends, floor loading often wins.
Pallet standard
Footprint
Typical use
20ft floor
40ft floor
EUR1 / Euro
120 × 80 cm
European distribution, the default across the EU
11
23–25
EUR2 / Industrial
120 × 100 cm
Heavier European industrial goods
10
20–21
GMA
48 × 40 in (121.9 × 101.6 cm)
North American grocery and retail
10
20–21
Asia standard
110 × 110 cm
Japan, Korea, much of South East Asia
10
20
Australia standard
116.5 × 116.5 cm
Australian domestic distribution
8
18
Half Euro
80 × 60 cm
Retail-ready display units
22
46–50
Floor counts assume single-layer loading with no overhang and modest clearance. Turning some pallets ninety degrees at the door end frequently adds one or two; the calculator tests that automatically.
Building the pallet
The tool works in two stages. First it fills the pallet: how many cartons fit on the deck footprint in the best orientation, how many layers fit inside your maximum load height once the deck height is subtracted, and therefore how many cartons per pallet. Then it fills the container with those pallets as rigid blocks, testing both pallet orientations and checking whether a second pallet will fit above the first.
Two settings deserve attention. Maximum load height is the total height of the loaded pallet including the deck, and it is usually set by your own warehouse racking or by the customer's, not by the container. Overhang is how far cartons may project beyond the deck edge — some operations allow 2 to 3 cm, many allow none at all, and overhanging cartons are dramatically more likely to be crushed in transit.
Patterns worth knowing
Block stacking — every carton aligned the same way. Maximum density, minimum stability. Fine for shrink-wrapped, uniform loads.
Brick or interlocked — alternate layers rotated so cartons bridge the joints below. Roughly 10 to 15% less dense, far more stable, and the standard choice for anything travelling by sea.
Pinwheel — cartons arranged around a central void. Useful when the carton footprint tiles awkwardly into the pallet, and it usually beats block stacking for oddly proportioned cartons.
Column stacking — cartons stacked directly on the corners below. Strongest vertically, because carton strength lives in the corner posts, but it needs good wrapping to stay together.
Double stacking
Doubling the pallets doubles the cargo in the box, so it is always worth checking. The test is arithmetic: twice the loaded pallet height must be less than the container internal height. A 164 cm loaded pallet cannot double stack in a 239 cm container; a 118 cm one can. The other test is not arithmetic: the bottom pallet must be able to carry the top one. Cartons crushed at the bottom of a double stack are the single most common palletised-cargo claim, so if the lower cartons are not rated for it, do not do it — or use a slip sheet and a load-bearing frame.
Three different weight limits, and they are not the same
Cargo weight has to satisfy several ceilings at once, and the lowest one wins. People plan against the container payload, get a clean answer, and then find the truck cannot legally leave the yard.
Container maximum payload. Maximum gross weight minus tare, stamped on the container's CSC plate. Around 28 tonnes for a 20ft and 26 to 27 for a 40ft.
Road gross-weight limit. The truck, trailer, container and cargo together. Commonly around 40 to 44 tonnes in the EU, 36 tonnes gross in the US without special permits, and lower in many other jurisdictions. This is very often the real constraint, and it means a 20ft box that is legally loaded to its payload may still be unroadable.
Axle weight limits. Even at legal gross weight, the load must be distributed so that no axle is overloaded. Concentrating heavy cargo at one end of a container is a classic way to fail a roadside check with a legal total weight.
Verified Gross Mass (VGM)
Since the SOLAS amendment took effect, no packed container may be loaded aboard a vessel without a verified gross mass declared by the shipper. VGM is the total: cargo, all packaging, pallets, dunnage, bracing, lashing, and the container's own tare. There are two permitted methods — weigh the packed container, or weigh all the contents and add the certified tare — and both need a documented, auditable process.
The calculator estimates VGM by adding cargo weight, pallet weights, your dunnage allowance and the container tare. Use it to check that your declared figure is in the right region. It is an estimate from your inputs, not a weighing, and it does not satisfy the regulation on its own.
The tolerance is tighter than people expect. Many carriers and terminals work to a few hundred kilograms of tolerance on the declared VGM. Guessing dunnage weight, forgetting pallets, or using a nominal carton weight instead of the actual gross weight will all put you outside it, and a rejected VGM means a missed sailing.
Weight distribution inside the box
Keep the centre of gravity low and central. Heavy cartons on the floor, light ones on top — for stability at sea as much as for the truck.
Spread heavy cargo along the length. A dense load concentrated in the door half overloads the trailer's rear axles even when the gross weight is legal.
Do not exceed the point-load rating. Container floors are rated for a forklift wheel load; concentrated machinery feet need spreader boards.
Brace anything that can move. A container rolls, pitches and heaves at sea. Cargo that shifts damages itself, the container, and occasionally the ship.
Chargeable weight, all four bases
Carriers bill on whichever is greater, actual weight or a volumetric equivalent. The divisor differs by mode, and knowing which one applies to your quote explains a lot of otherwise baffling invoices.
Mode
Basis
Rule
Bites when
Sea LCL
Weight or Measure (W/M)
1 CBM against 1,000 kg — you pay the higher
Cargo is lighter than 1 tonne per cubic metre
Air freight
Volumetric
L × W × H in cm ÷ 6,000 = volumetric kg
Density is below about 167 kg per CBM
Road (Europe)
Volumetric
cm³ ÷ 3,000 = kg
Density is below about 333 kg per CBM
Courier / express
Volumetric
cm³ ÷ 5,000 = kg
Density is below about 200 kg per CBM
Full container load is the exception: you pay for the box, so density stops mattering the moment you fill one. That is precisely why the LCL-to-FCL break-even is worth calculating rather than assuming.
Before the container arrives
Inspect it. Check for holes, damp, odour, previous cargo residue and a working door seal. Photograph the interior and the CSC plate. A container that leaks will ruin the load and the argument about who pays will not go your way without evidence.
Verify the tare. Read it off the door, do not assume the standard figure. It goes into your VGM.
Have the plan on paper. The crew should know the pattern, the layer count and the orientation before the first carton moves. Re-planning mid-load is how loads end up 80% efficient.
Stage the cargo. Cartons sorted, counted and positioned in loading order. Searching for stock with a container on demurrage is expensive.
During stuffing
Load heaviest first, lowest and most central. Weight distribution is decided at the start, not at the end.
Build complete layers. A part-built layer beneath a full one is an invitation to collapse.
Keep the pattern consistent. Consistency is what makes the count verifiable — a crew can confirm 24 × 5 × 6 by looking; nobody can verify 1,412 loose cartons.
Fill voids as you go. Airbags, dunnage or void-fill between blocks, not left until the doors will not shut.
Count at the door. Tally as cartons cross the threshold, not from the pick list. Discrepancies found at destination cost far more than the ten minutes of counting.
Photograph the load. Every few layers and at final close. This is the evidence base for any damage claim.
Brace the door end. The last metre is where cargo moves. Bars, straps or airbags — not hope.
Seal and record. Photograph the seal number in place. It goes on the bill of lading and it is the first thing anyone checks.
Common failures and what causes them
What went wrong
Usual cause
Prevention
Crushed bottom cartons
Stack height exceeded the carton compression rating
Set and honour a stacking limit; use the tool's limit field
Cargo shifted in transit
Voids not filled, door end unbraced
Airbags, dunnage, load bars; plan the void, do not discover it
Container rejected for weight
Planned against payload, not the road limit
Check gross road weight as well as container payload
Condensation damage
Warm humid air sealed in with hygroscopic cargo
Desiccants, ventilation, avoid stuffing in the rain
Fewer cartons loaded than planned
Real clearances ignored in the plan
Set realistic clearance and door-end space up front
Doors will not close
Cumulative creep from imperfect alignment
Leave the door-end allowance; check alignment every few layers
Getting the last few percent
The gap between a plan and a stuffed container is discipline, not cleverness. Crews that consistently hit their plan share the same habits: they build to a written pattern, they check alignment every few layers rather than at the end, they fill voids continuously, and they stop and re-measure when something does not sit right instead of forcing it. If your loads routinely come in below plan, the fix is almost never a better algorithm.
The LCL versus FCL decision
Less than Container Load means your cargo shares a box with other shippers and you pay by volume or weight, whichever is greater. Full Container Load means you take the whole box at a flat rate. Somewhere between those two there is a crossover volume, and the calculator works it out from your own rates rather than from a rule of thumb.
The arithmetic is simple: break-even CBM = FCL all-in cost ÷ LCL rate per CBM. At an FCL rate of 2,200 and an LCL rate of 95 per CBM, the crossover is about 23 CBM — which is more than a 20ft container holds, meaning FCL wins well before you fill the box. At an LCL rate of 55 the crossover moves to 40 CBM and LCL stays competitive much longer. Rates move, so the answer moves.
Why the raw crossover understates the case for FCL
Destination charges. LCL carries deconsolidation and CFS handling fees at destination that are often quoted separately, sometimes not quoted at all until the invoice.
Time. LCL waits for consolidation at origin and deconsolidation at destination — typically five to ten extra days end to end.
Handling risk. Your cargo is loaded, unloaded and reloaded alongside other people's, and it can be crushed by theirs.
Rounding. LCL volumes are usually rounded up, and minimum charges apply on small shipments.
Certainty. An FCL box seals at your dock and opens at theirs. That has a real value that does not appear on any rate sheet.
The counterweight is capital: FCL means larger order quantities, more stock sitting in a warehouse, and cash committed earlier. For a small or seasonal business that can outweigh the freight saving entirely.
Cost per unit is the number that matters
Freight per container is a procurement number. Freight per carton — or better, per saleable unit — is the number that belongs in your pricing. The calculator divides the container cost by the cartons actually loaded, which is why a plan that finds 4% more capacity shows up directly as a 4% lower freight cost per unit. Run the equipment comparison and you will often find the cheapest box per container is not the cheapest box per carton.
A worked example, using this tool's own defaults. An order of 900 cartons of 50 × 40 × 35 cm at 2,200 per 40ft container. Packed in one fixed orientation only 720 fit, so the order needs two containers: 4,400 of freight, about 4.89 per carton. The mixed-orientation partition fits 912 in the same box, so the order goes in one: 2,200 of freight, about 2.44 per carton. Half the freight cost per unit, from turning the carton and filling two leftover slabs. That is the size of prize that justifies doing this properly.
Levers worth pulling before you accept a second container
Change the equipment. A High Cube adds a layer for many carton heights, at a small rate premium.
Change the carton. If you control the packaging, a few centimetres in the right dimension can be worth hundreds of pieces. Design the carton around the container, not the product.
Change the pallet pattern. Brick or pinwheel patterns often gain a layer over block stacking on awkward footprints.
Trim the order. If you are 60 cartons over, shipping 1,400 instead of 1,460 in one box is usually better economics than a second container a quarter full.
Drop the pallets. Floor loading recovers the deck height and often a whole layer, at the cost of handling time at both ends.
Combine shipments. Two part-loads to the same destination in one box beats two half-empty containers.
Terms used in this tool
Block stacking
Placing every carton on a pallet in the same orientation. Densest pattern, least stable.
Bracing / dunnage
Airbags, timber, boards or straps used to fill voids and stop cargo moving in transit.
CBM
Cubic metre. The standard volume unit in freight. Length × width × height in metres.
Chargeable weight
The greater of actual weight and volumetric weight, which is what the carrier bills on.
Clearance
The working gap left between cargo and the container walls, deliberately unused space.
Compression rating
The load a carton can bear from above before it crushes. Sets the stacking limit.
CSC plate
The safety approval plate on a container recording its tare, maximum gross and inspection status.
Door aperture
The clear opening at the container doors, always smaller than the internal cross-section.
FCL
Full Container Load. You take the whole box at a flat rate regardless of how full it is.
Floor loading
Stuffing loose cartons directly into the container without pallets. Denser, slower to handle.
High Cube
A container about 30 cm taller internally than the standard equivalent.
Interlocking / brick pattern
Alternating layer orientations so cartons bridge the joints below, for stability.
LCL
Less than Container Load. Your cargo shares a container and you pay by volume or weight.
Maximum gross weight minus tare — the most cargo a container may legally carry.
Pinwheel
A pallet pattern with cartons arranged around a central void, useful for awkward footprints.
Stuffing
The act of loading cargo into a container. Also called vanning.
Tare weight
The weight of the empty container, stamped on the CSC plate.
TEU
Twenty-foot Equivalent Unit. A 40ft container is 2 TEU.
Unit load
Cargo consolidated into a single handleable block, usually a wrapped pallet.
Utilisation
The proportion of container capacity used, measured by volume or by weight.
VGM
Verified Gross Mass. The declared total weight of a packed container, required before vessel loading.
Volumetric weight
Volume converted to a weight equivalent using a mode-specific divisor.
Frequently asked questions
Why does my warehouse fit more than the calculator says?
Good crews beat a geometric plan by compressing soft goods, angling cartons in leftover voids, and filling the top slab by hand in ways no partition model captures. That is a real skill and worth more than the algorithm. Use the calculator's number as the planning baseline, then record what your team actually achieves and apply that as your own efficiency factor.
Why does it fit fewer than a competitor's calculator?
Usually because the other calculator ignores the constraints you set. Clearance, door-end space, stacking limits and the payload cap all reduce the number, and all of them exist for good reasons. Set them to zero and you will get the pure geometric maximum — which is also the number that gets crews into trouble.
Can I mix different products in the same container?
Yes, and the tool handles it with multiple cargo lines. Bear in mind that interleaving different carton sizes is genuinely harder than packing one, which is why the combined figure applies the mixed-load efficiency you set. Where the SKUs differ a lot in size, plan them as separate blocks within the container rather than trying to interleave them.
How accurate are the internal dimensions?
They are widely used planning figures accurate to a few centimetres. That is fine for almost every decision. When a load is marginal — when one more centimetre would add a row — get the specification for the actual container number you have been allocated, because the variation between builders is real.
Should I use the High Cube?
Run the equipment comparison and let the numbers decide. A High Cube adds about 30 cm of internal height, which only helps if your carton height divides usefully into it. For 35 cm cartons it adds a whole layer and is an obvious win; for 45 cm cartons it adds nothing at all.
What stacking limit should I set?
Ask your packaging supplier for the carton's compression rating and work back from it, allowing a safety factor for humidity — corrugated board loses a substantial part of its strength in high humidity, which is exactly what a container hold provides. If you have no figure at all, three to five layers is a common conservative range for typical retail cartons, but it is a guess and worth replacing with a real number.
Does the tool plan the actual stow position?
It gives you a pattern and a layer schedule, which is what a stuffing crew works from, and it visualises the resulting stack. It does not generate a carton-by-carton stow diagram with individual coordinates — that is the territory of dedicated load-planning software integrated with your WMS.
What is a good utilisation figure?
Above 90% by volume is excellent and hard to sustain. 80 to 85% is a normal, well-run load. Below 70% means something is worth changing: the equipment, the carton, the pallet pattern or the order quantity. If weight utilisation is the high number, ignore volume entirely — you are shipping density, not space.
Are saved scenarios stored on your servers?
No. Saved scenarios live in your own browser's local storage on your own device. They are not transmitted anywhere, they are not visible to us, and clearing your browser data removes them. Nothing you type into this tool leaves your machine.
Can I use the output commercially?
Yes. Export the CSV, put the plan in a quotation, hand it to your warehouse. Present it as a planning estimate rather than a guarantee, and verify payload and VGM against a weighbridge before the container ships.
About Container Stuffing / Loading Plan Calculator
The Container Stuffing / Loading Plan Calculator turns carton dimensions into a loading plan you can hand to a warehouse team: cartons per row, per column, per layer, number of layers, total pieces per container, containers required, and the volume and weight utilisation of each. It covers twelve equipment types from a 20ft standard through High Cubes, reefers, open-tops, flat racks and road trailers, and it handles both floor-loaded cartons and palletised unit loads.
Underneath, it tests every permitted carton orientation and then fills the three leftover slabs of the container with whichever orientation suits each one — a mixed-orientation partition that regularly finds several percent more capacity than the single-orientation arithmetic most calculators stop at. On top of the geometry it runs the commercial checks that decide whether a plan is shippable: payload, Verified Gross Mass, road gross-weight limits, chargeable weight on four different bases, cost per cubic metre, and the LCL versus FCL break-even for your rates.
Features
Twelve equipment types: 20ft and 40ft standard, 40ft and 45ft High Cube, 20ft and 40ft reefer, open-top, flat rack, and EU and US road trailers, each with real internal dimensions, door aperture, tare and payload.
Multi-SKU cargo lines: Add a line per product with its own dimensions, weight, quantity, stacking limit and this-way-up constraint.
Mixed-orientation packing: All six orientations tested, then the leftover length, width and height slabs filled independently for extra capacity.
Pallet mode: EUR1, EUR2, GMA, Asian and custom pallets — cartons per pallet, then pallets per container, with optional double stacking.
3D load visualisation: An isometric render of the actual stack plus a floor plan showing the main block and the leftover slabs.
Weight and compliance checks: Payload test, VGM estimate, road gross-weight warning and per-container weight utilisation.
Chargeable weight: Sea W/M, air 1:6000, road 1:3000 and courier 1:5000 shown side by side.
Commercial analysis: Cost per container, cost per CBM, cost per carton and an LCL versus FCL break-even volume.
Equipment comparison: Every container type ranked for your cargo so you can see which box is genuinely cheapest per unit.
Export and reuse: CSV download, clipboard copy, clean print or PDF, and saved scenarios in your own browser.
How to Use
Pick your equipment — start with the container or trailer type you expect to book. You can compare the rest later.
Choose your units — centimetres and kilograms, or inches and pounds. Everything converts.
Add your cargo lines — one per SKU, with carton length, width, height, gross weight, quantity, maximum stack height and whether the carton may be laid on its side.
Switch to pallet mode if you ship palletised — pick the pallet standard, set your maximum load height and whether pallets can be double stacked.
Enter your commercial inputs — freight cost per container, LCL rate per CBM and all-in FCL rate, and the mixed-load efficiency you expect from your warehouse.
Read the loading plan — cartons per row, per layer, layers, total per container, containers required, and both utilisation figures.
Check the visual — the 3D view shows the stack, the floor plan shows how the main block and the leftover slabs are arranged.
Compare equipment — the comparison tab ranks every container type by cost per carton for your specific cargo.
Export — download the CSV for your file, or print a clean plan that contains only the results.
Examples
Example 1 — the orientation gain, on the tool default: A carton of 50 × 40 × 35 cm in a 40ft standard. Packed in a single orientation the best you can do is 720 cartons. The calculator turns the carton so the 35 cm edge runs along the container length, giving a main block of 34 deep × 4 wide × 5 layers = 680, then fills the 35 cm leftover strip beside the last column with 116 more and the 39 cm gap above the top layer with another 116. Total 912 per container, 94.5% of the volume. On a 900-carton order that is the difference between two containers and one — 26.7% more cargo in the same box, from nothing but reorientation.
Example 2 — the half-empty second container: The same carton, but an order of 1,400 at 12 kg each. Two 40ft containers are needed and the second is only 54% full, carrying 488 cartons. Weight utilisation is just 41%, so the box is running out of space long before it runs out of payload. That is the moment to check the alternatives: a 40ft High Cube fits 995 (an extra layer across most of the floor), and trimming the order to 912 removes a container from the invoice entirely.
Example 3 — a weight-limited load: A tile manufacturer ships 30 × 30 × 12 cm cartons at 22 kg. The geometry says 2,401 cartons fit a 20ft, but at 22 kg each that would be 53 tonnes against a payload of 28.2. Weight is the binding constraint, so the tool caps the load at 1,279 cartons — 99.8% of the payload and only 41.7% of the volume. The right answer here is not a bigger box; it is more boxes, each loaded light.
Example 4 — palletised export: A food exporter loads EUR1 pallets at 120 × 80 cm with 30 × 25 × 20 cm cartons to a maximum height of 150 cm. Pallet mode returns 16 cartons per layer, 5 layers, 80 cartons per pallet, and a loaded pallet height of 139.4 cm. A 40ft container takes 25 of those pallets, so 2,000 cartons per box. Double stacking is impossible — two pallets would be 279 cm against 239 cm of internal height — and that constraint only appears once the arithmetic is done.
Benefits
Right-size every shipment: Know exactly how many cartons fit and how many containers you actually need before you book.
Stop paying for air: A few percent of extra utilisation found by reorientation is a real saving on every container you ship.
Avoid the second container: See immediately when trimming an order or changing equipment removes a whole box from the invoice.
Catch overloads before the terminal does: Payload, VGM and road-limit checks in the plan rather than at the weighbridge.
Give the warehouse something usable: A row, column and layer schedule with a visual, not just a total.
Make the LCL-versus-FCL call with numbers: A break-even volume calculated from your own rates.
Free, private and instant: No sign-up, no upload, everything runs in your browser.
Frequently Asked Questions
How many boxes fit in a 20ft container?
It depends entirely on the carton size and how the cartons are turned. A 20ft standard container has usable internal dimensions of roughly 5.90 m long, 2.35 m wide and 2.39 m high, giving about 33 cubic metres. A common 50 × 40 × 35 cm carton yields around 430 to 470 pieces — the pure volumetric ceiling is 473, so any calculator quoting more than that is wrong. This calculator tests every permitted orientation and a mixed-orientation partition, so it gives the actual number for your carton rather than a rule of thumb.
What is the difference between a 40ft and a 40ft High Cube?
Length and width are effectively identical at about 12.03 m by 2.35 m. The difference is height: a 40ft standard is about 2.39 m internally, a High Cube about 2.69 m. That extra 30 cm often buys a whole additional layer of cartons, which is why the High Cube is usually the better value even at a small rate premium. The calculator shows both side by side in the equipment comparison so you can see whether the extra layer actually materialises for your carton height.
How is container utilisation calculated?
Volume utilisation is the cargo volume actually loaded divided by the container internal volume, expressed as a percentage: (carton volume × cartons loaded) ÷ container capacity × 100. Weight utilisation is cargo weight divided by the maximum payload. Both matter. A load can be 95% full by volume and only 30% by weight, or the reverse, and the binding constraint tells you what to optimise. Real-world loads rarely exceed about 85 to 90% by volume because of stacking gaps, dunnage, bracing and the space needed to work.
What are standard container internal dimensions?
Typical internal figures are: 20ft standard about 5.90 × 2.35 × 2.39 m; 40ft standard about 12.03 × 2.35 × 2.39 m; 40ft High Cube about 12.03 × 2.35 × 2.69 m; 45ft High Cube about 13.56 × 2.35 × 2.69 m. Reefers are noticeably smaller inside because of insulation and the machinery unit. Every one of these varies by a few centimetres between manufacturers and carriers, so treat them as planning values and confirm with the container operator when a load is marginal.
Does the calculator account for weight limits?
Yes. Each equipment type carries its tare weight and maximum payload, and the tool checks your cargo weight against the payload, flags an overload, and reports the Verified Gross Mass — cargo plus pallets plus dunnage plus container tare. It also warns when the loaded weight is likely to breach common road gross-weight limits, which frequently bite well before the container payload does.
Why does box orientation matter so much?
Because containers are fixed boxes and cartons are not. Turning a carton so that a different edge runs along the container length can change how many fit per row, per column and per layer, and the effect compounds across all three axes. A five-centimetre change in the wrong dimension can lose you an entire layer. The calculator evaluates all six orientations (or the two that keep the carton upright if you set a this-way-up constraint) and then also tries filling the leftover strips with a different orientation, which typically adds a few percent on top.
What is the mixed-orientation partition the tool uses?
After choosing the best single orientation for the main block, the container still has three leftover slabs: one beyond the end of the last row, one beside the last column, and one above the top layer. The tool partitions those three regions and fills each with whichever orientation fits it best. It is a heuristic rather than a proven optimum — true 3D bin packing is NP-hard — but it is a genuine improvement on the naive single-orientation calculation and it produces a plan a warehouse team can actually follow.
How many pallets fit in a container?
For standard EUR1 pallets at 120 × 80 cm, a 20ft container takes 11 in a single layer and a 40ft takes 23 to 25 depending on how they are turned and how much clearance you allow. For 120 × 100 cm industrial pallets it is about 10 in a 20ft and 20 to 21 in a 40ft. Double-stacking doubles those figures when the cargo and the pallet height allow it. Switch the tool to pallet mode and it works out cartons per pallet and then pallets per container for your exact dimensions.
What is VGM and why does the tool calculate it?
Verified Gross Mass is the SOLAS requirement that the total weight of a packed container — cargo, packaging, pallets, dunnage and the container tare — be verified and declared to the carrier before it can be loaded aboard a vessel. Get it wrong and the box does not sail. The tool estimates VGM from your cargo weight, pallet weights and a dunnage allowance plus the equipment tare, giving you a figure to sanity-check against a weighbridge reading.
What is chargeable weight and which one applies to me?
Carriers charge on whichever is greater, actual weight or volume converted to a weight equivalent. Sea LCL uses weight or measure: one cubic metre against one tonne, and you pay the higher. Air freight divides volume in cubic centimetres by 6,000 to get a volumetric kilogram. Road freight in Europe commonly uses 3,000, and courier services often use 5,000. The tool shows all of these so you can see which basis your quote is really built on.
When does LCL become more expensive than a full container?
At the break-even volume, which the tool calculates for you. Enter your LCL rate per cubic metre and your all-in FCL rate and it tells you the CBM at which taking the whole box becomes cheaper. In most trades the crossover sits somewhere between 12 and 18 CBM on a 20ft, but it moves with the rate environment, and LCL also carries extra destination charges and handling time that raw rate comparison misses.
Can I calculate a mixed load with several different products?
Yes. Add a cargo line for each SKU with its own dimensions, weight, quantity and stacking rules. The tool packs each line and then reports a combined summary. Because interleaving different carton sizes in one container is genuinely harder than packing one, the combined figure applies a mixed-load efficiency factor that you control — 85% is a reasonable default and experienced warehouse teams often beat it.
What does the stacking limit do?
It caps how many cartons may sit on top of each other, which is a crush-strength constraint rather than a geometric one. Set it to 3 and the tool will never build a column more than three cartons high even if the container height would allow six. Ignoring stacking limits is one of the most common causes of crushed cargo and rejected claims, because a carton rated for a three-high stack does not become stronger in a container.
Should I load to 100% of the container volume?
No, and you cannot. Between cartons there are gaps, at the door end you need working space, and unless the load fills the container tightly you must brace it so it does not shift at sea. A plan at 90% volume utilisation is excellent, 80 to 85% is normal, and anything above 95% on paper usually means the calculation has not allowed for reality. Leave room for airbags, dunnage and the last-minute carton that does not quite fit.
Is my data stored anywhere?
No. Every calculation runs in your browser. Cargo dimensions, weights, quantities and rates are processed locally and never transmitted. Saved scenarios are stored only in your own browser storage on your own device and can be cleared at any time.